Table 2.

Effects of the in vivo administration of androgen hormones on early follicular development.

Animal	Methodology used	Main results	Reference
Non-human primate	Subcutaneous implants containing testosterone (4 mg/kg animal weight/day) for 3 days, (400 μg/kg animal weight/day) for 10 days, (20 g/kg animal weight/day) for 5 days, or dihydrotestosterone (145 μg/kg animal weight/day) for 5 days.	Increased follicular retrieval, growth, and survival. Increased theca and granulosa cell proliferation.	Vendola et al., 1998 [70]
	Subcutaneous implants containing testosterone (20 μg/kg animal weight/day) or dihydrotestosterone (145 μg/kg animal weight/day) for 5 days.	Increased expression of mRNA for IGF-I and for IGF-I receptor in granulosa and theca cells of growing follicles.	Vendola et al., 1999 [18]
	Subcutaneous implants containing testosterone (20 μg/kg animal weight/day) or dihydrotestosterone (145 μg/kg animal weight/day) for 5 days; testosterone (400 μg/kg animal weight/day) for 3 or 10 days.	Increased follicular retrieval and expression of IGF-I mRNA and of IGF-I receptor in oocytes of primordial follicles.	Vendola et al., 1999 [19]
	Subcutaneous implants containing testosterone (4 mg/kg animal weight/day) for 3 days or testosterone (0.4 mg/kg animal weight/day) for 10 days.	Increased expression of FSH receptor mRNA in granulosa cells of growing follicles.	Weil et al., 1999 [66]
Swine	Intramuscular administration of dihydrotestosterone (60 μg/kg animal weight) for the first 3 days of the early follicular phase or for the last 3 days of the late follicular phase; dihydrotestosterone (6 μg/kg animal weight) administered from the 13th day of the estrous cycle to the next estrus.	Increased ovulatory rate and increased expression of FSH receptor mRNA in periovulatory follicles.	Cárdenas et al., 2002 [73]
Rodent	Administration of a subcutaneous implant containing dihydrotestosterone (83 μg/kg animal weight/day) for 90 days.	Increased follicular retrieval in preantral follicles. Increased potential for in vitro development of preantral follicles.	Xue et al., 2012 [74]